Synthesis of the diastereoisomers of 1,2-dipalmitoyl-sn-glycero-3-thiophosphorylethanolamine and their stereospecific hydrolysis by phospholipases A2 and C.
A convenient three-step synthesis of the phosphorothioate analogue of phosphatidylethanolamine is described. The reaction pathway involves the conversion of a 1,2-diacyl-sn-glycerol to its corresponding thiophosphoric acid dichloride by using PSCl3 in the presence of a tertiary base. Treatment of the dichloride with ethanolamine results in the formation of a cyclic thiophosphoramidate which, upon acidification, undergoes P--N cleavage, giving rise to 1,2-diacyl-sn-glycero-3-thiophosphorylethanolamine. 31P NMR reveals that both diastereoisomers are present in equivalent amounts. It is not possible, however, to separate the two isomers by high-pressure liquid chromatography. 31P NMR amd high-pressure liquid chromatography are used to show that phospholipases A2 and C exhibit absolute and opposite stereoselectivity in the hydrolysis of the pair of diastereoisomers.
D001409:Bacillus cereus / Q000201:enzymology; D001514:Bee Venoms; D002851:Chromatography, High Pressure Liquid; D009682:Magnetic Resonance Spectroscopy; D010714:Phosphatidylethanolamines; D010740:Phospholipases / Q000378:metabolism*; D010741:Phospholipases A / Q000378:metabolism*; D013237:Stereoisomerism; D013379:Substrate Specificity; D010738:Type C Phospholipases / Q000378:metabolism*
C035164:1,2-dipalmitoylglycero-3-thiophosphorylethanolamine; D001514:Bee Venoms; D010714:Phosphatidylethanolamines; D010740:Phospholipases; D010741:Phospholipases A; D010738:Type C Phospholipases